Could the lateral transfer of nutrients by outbreaking insects lead to consequential landscape‐scale effects?

Abstract

Citation: Landry, J.-S., and L. Parrott. 2016. Could the lateral transfer of nutrients by outbreaking insects lead to consequential landscape-scale effects? Ecosphere 7(3):e01265. 10. 1002/ecs2.1265 Abstract. The processes that transfer nutrients laterally over large distances are limited within terrestrial ecosystems. Here, we present the hypothesis that outbreaking insects can sometimes transport consequential amounts of embodied nutrients over long distances, thereby connecting ecological dynamics across space and leading to potential emergent effects at the landscape scale that have not been specifically addressed heretofore. Based on previously published data on insect population density, individual body mass, and nutrient content, we present initial quantitative estimates of nitrogen and phosphorus fluxes for various outbreaking insect species in different ecosystems. The results suggest that during the phases of major population change within an outbreak cycle, this process may transfer, over a given area, amounts of nutrients that exceed annual input from contemporaneous levels of atmospheric deposition, particularly for phosphorus. In addition, the relative strength of the process was likely even higher in the preindustrial era, especially for nitrogen, due to a weaker anthropogenic influence on atmospheric deposition at that time. The values we have found are comparable to the results from previous studies on 2-D nutrient fluxes by other animals and that have been considered consequential for ecosystem processes. We further illustrate the implications of the process for the spatial distribution of nutrients and resulting ecological complexity and argue that the process is inherently scale dependent, contrary to vertical fluxes like atmospheric deposition. Moreover, we provide suggestions for future studies, both empirical and theoretical, that would better quantify the strength of the process and assess its implications. Given that the productivity of most natural terrestrial ecosystems depends primarily on locally recycled nutrients and that spatial source-sink nutrient dynamics has been shown to have important ecological consequences, the long-distance lateral transfer of nutrients by outbreaking insects appears like a relevant landscape-level process worthwhile of more specific attention.

Implementation of a Marauding Insect Module (MIM, version 1.0) in the Integrated BIosphere Simulator (IBIS, version 2.6b4) dynamic vegetation–land surface model

“…Bright et al, 2013;Maness et al, 2013;Mikkelson et al, 2013a;Pugh and Gordon, 2013;Metcalfe et al, 2014;Reed et al, 2014;Seidl et al, 2014;Turcotte et al, 2014;Vanderhoof et al, 2014;Landry and Parrott, 2016). Yet the simulation of insect-induced plant damage in climate models has lagged behind the simulation of fire, even though the two disturbance types were recognized as climate-related phenomena worthwhile of explicit representation in dynamic global vegetation models (DGVMs) more than 15 years ago (Fosberg et al, 1999).…”

Mass seasonal bioflows of high-flying insect migrants

“…Such "common orientation" was indeed highly prevalent in the larger 6 insects (table S1) What are the implications of this high-altitude insect movement? Insect bodies are typically comprised of 10% nitrogen and 1% phosphorus by dry weight (20), and as such they represent a rich source of nutrients which can be limiting for plant productivity (11). The 3200 tons of biomass moving annually above our study region contains ~100,000 kg of N and 10,000 kg of P, representing 0.2% of the surface deposits of N and 0.6-4.7% of P from the atmosphere, comprising 5.78 x 10 12 Joules of energy (15).…”

Massive windborne migration of Sahelian insects: Diversity, seasonality, altitude, and direction

“…Long-distance migration of insects has been recognized as a pivotal influence affecting food security (Glick, 1939; Rainey, 1989; Cheke et al, 1990; Chapman et al, 2004a; Reynolds et al, 2006; Maiga et al, 2008; Dingle, 2014), public health (Garms et al, 1979; Sellers, 1980; Ming et al, 1993; Ritchie & Rochester, 2001; Eagles et al, 2013; Huestis et al, 2019), and ecosystem vigor (Green, 2011; Landry & Parrott, 2016). We follow the definition of migration (sometimes considered as dispersal) as persistent movements that are unaffected by immediate cues for food, reproduction, or shelter, that have a high probability to relocate the animal in a distinct environment (Dingle & Drake, 2007; Dingle, 2014; Chapman et al, 2015).…”